Effect of different P levels on seed yield of spring mungbean, Vigna radiata (L)

The treatments comprised of the five phosphorus levels including a control viz. 0, 40, 50, 60 and 70 kg P per ha. The observations were recorded on the basis of randomly selected five plants, which were randomly selected and labeled in each plot. The first irrigation was applied after 35 days of sowing, while the second irrigation was given after 20 days of first irrigation. The results showed that application of phosphorus to certain rates had significant (P less than 0.01) effect on the entire growth and seed yield contributing characters of mungbean. The highest phosphorus level of 70 kg per ha produced significantly maximum seed germination of 12.00 m2, plant height 41.65 cm, 13.55 average number of branches per plant, 37.66 average number of seeds per plant, 301.50 average number of seeds per plant, 16.28 g average weight of seeds per plant, 33.31 g seed index value, 2556.65 kg seed yield per ha and 41.35 percent harvest index. The phosph orus when applied at the rate of 60 kg per ha, produced 11.75 m2 average seed germination, 40.89 cm plant height, 13.58 average number of branches per plant, 36.41 average number of pods per plant, 295.05 average number of seeds per plant, 16.22 g average weight of seeds per plant, 33.26 g seed index value, 2544.42 kg seed yield per ha and 41.20 percent harvest index. The phosphorus when applied at the rate of 50 kg per ha, produced 10.70 m2 average seed germination, 38.42 cm plant height, 11.61 average number of branches per plant, 31.03 average number of pods per plant, 251.50 average number of seeds per plant. 14.96 g average weight of seeds per plant, 32.11 g seed index value, 2245.85 kg seed yield ha s and 38.26 percent harvest index. Similarly, the lowest phosphorus rate of 50 kg per ha, produced 10.00 m2 average seed germination, 36.73 cm plant height, 10.83 average number of branches per plant, 27.71 average number of pods per plant, 190.37 average number of seeds per plant, 12.34 g average weight of seeds per plant, 30.24 g seed index value, 1836.30 kg seed yield per ha and 36.30 percent harvest index. The control treatment produced 9.00 m2 average seed germination, 26.90 cm plant height, 7.37 average number of branches per plant, 18.46 average number of pods per plant, 122.85 average number of seeds per plant, 9.94 g average weight of seeds per plant, 27.93 g seed index value, 144.75 kg seed yield per ha and 29.93 percent harvest index. The above values were lowest in the respective treatments for all the parameters studied as compared to phosphorus treated plots. It was concluded that there was a linear and significant (P less than 0.01) effect of increasing P levels up to 60 kg per ha on seed yield per ha, further increase in P levels did not prove beneficial and statistically the differences in the values for almost all the characters between 70 kg and 60 kg P levels were-non-significant (P greater than 0.05). The above trend of effe ctiveness makes it obvious that P application for mungbean cultivation up to 60kg per ha was an optimum level.